CN115711634A - Sensitivity-enhanced sensing optical cable - Google Patents

Abstract

The invention belongs to the technical field of communication optical cables, and provides a sensing optical cable with enhanced sensitivity. The optical fiber unit in the cable is helically wound and arranged to ensure the stable transmission performance of the optical cable, and at the same time increase the length of the optical fiber within the unit length of the optical cable and improve the detection sensitivity. ; A continuous array of grooves is spirally distributed on the surface of the central strength member, and the optical fiber unit is filled in the grooves of the groove array, which reduces the gap between the central strength member and the sheath, and reduces the air in the gap. The resistance to sound waves improves the sensitivity of sound wave signal detection, and at the same time fills the polyester fiber composite tape of single-sided composite polyester film along the inner surface of the groove, and the polyester film surface of the polyester fiber composite tape is close to the place. As for the inner surface of the groove, the non-composite polyester film surface has porous characteristics, and the surface porous characteristics of the polyester fiber composite tape are used to improve the sound wave absorption effect, forming a sound-accommodating cavity in the entire groove, and improving the sensitivity of optical fiber detection.

Description

A Sensing Optical Cable with Enhanced Sensitivity

technical field

The present application relates to the technical field of communication optical cables, in particular to a sensing optical cable with enhanced sensitivity.

Background technique

With the development of optical fiber technology, optical fiber is no longer limited to the function of communication medium. Optical fiber sensing technology has developed rapidly along with the development of optical fiber communication technology. It uses light waves as the carrier and optical fiber as the medium to sense and transmit the external measured Novel sensing technology for signals. In the future, optical cable products based on distributed optical fiber sensing will be widely used because they can be well connected to optical communication networks and have the characteristics of economy, flexibility, continuity, long distance, high precision and real-time monitoring. Detection and security in the fields of power cables, oil pipelines, tunnel subgrades, building bridges, structural health, geotechnical engineering, dam hydrology, marine exploration, etc.

The existing sensing optical cable is used as the carrier of the optical fiber distributed sensing system. In the actual application process, most of the optical fibers in the cable are placed directly. The detection sensitivity is not high. At the same time, affected by the application scenario, the sensing optical cable needs to have certain mechanical strength, such as tensile and lateral pressure resistance, to avoid damage to the optical cable during laying.

Contents of the invention

In view of this, the purpose of the present application is to provide a sensing optical cable with enhanced sensitivity, which can solve the problems in the background technology.

An embodiment of the present application provides a sensing optical cable with enhanced sensitivity. The sensing optical cable includes a central strength member and an optical fiber unit layer outside the central strength member. The central strength member is an elastomer or an inner nested metal or non- The thermoplastic elastic material of the metal element, the optical fiber unit layer includes an optical fiber unit that is continuously helically wound around the central strength member; the surface of the central strength member is spirally distributed with a continuous groove array along the length direction, and the optical fiber unit is filled in the In the groove of the above-mentioned groove array, the maximum depth and maximum width of the groove should not be less than the diameter of the optical fiber unit, and when a single optical fiber unit is accommodated, the maximum depth H and maximum width W of the groove satisfy: d≤H≤ d+d ₀ , d≤W≤d+d ₀ , where d is the diameter of the fiber unit; when n fiber units are accommodated, the size range of the groove satisfies: d _f <H≤d _f +d ₀ , where: n≥ 2. d _f is the equivalent diameter of n fiber units; d ₀ is the free coefficient, that is, the maximum vertical distance between the fiber unit and the inner surface of the groove after filling the groove, 0≤d ₀ ≤d; along the groove The inner surface of the polyester fiber composite belt is filled with a single-sided composite polyester film, the composite polyester film surface of the polyester fiber composite belt is airtight, and the non-composite polyester film surface of the polyester fiber composite belt has porous characteristics The polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, and the non-composite polyester film surface of the polyester fiber composite tape faces the optical fiber unit.

In some embodiments, the transverse section of the groove is arc-shaped and square, and the maximum depth and maximum width of the groove should not be smaller than the diameter of the optical fiber unit.

In some embodiments, the sensing optical cable includes a plurality of repeating segments of equal length, and the winding pitch of the optical fiber units in the repeating segments is set to vary.

In some embodiments, the array of grooves has more than two grooves, the grooves of the array of grooves have a first distance d ₁ ; the groove arrays have a second distance d2, 0≤ d1<d2.

In some embodiments, the fiber optic unit is in the shape of a flat ribbon.

In some embodiments, the number of bare optical fibers in the optical fiber unit is at least one, and the bare optical fibers are uniformly spaced and axially continuously distributed in the flat ribbon of the optical fiber unit, or the bare optical fibers are distributed in the flat ribbon of the optical fiber unit There is a continuous sinusoidal distribution in the flat strip.

In some embodiments, the optical fiber unit layer is covered with a first wrapping tape and a first outer sheath in sequence from the inside to the outside, and a reinforcing element is arranged in the first outer sheath, and the reinforcing element As metal elements or fiber reinforced plastics (FRP).

In some embodiments, the optical fiber unit layer is covered with a first wrapping tape, a first outer sheath, an outer armor layer, a second wrapping tape, and a second outer sheath sequentially from inside to outside.

The beneficial effects that the present application can achieve.

This application provides a sensing optical cable with enhanced sensitivity. The optical fiber unit in the cable is helically wound and arranged to ensure the stable transmission performance of the optical cable, and at the same time increase the length of the optical fiber within the unit length of the optical cable, further broaden the detectable range, and improve Detection sensitivity; at the same time, the central reinforcement is made of a sensitive material, which can reduce the loss of external transmission energy and improve the detection sensitivity of the sensing optical cable; furthermore, in this application, a continuous array of grooves is distributed on the surface of the central reinforcement to accommodate Multiple optical fiber units, increase the test signal channel, in case of fiber breakage, provide a backup line, and at the same time, the optical fiber unit is filled in the groove, so compared with the direct helical winding of the optical fiber unit on the surface of the central strength member , reducing the gap between the central reinforcement and the sheath, reducing the resistance of air in the gap to sound waves, improving the sensitivity of sound wave signal detection, and the distance between the optical fiber unit and the inner surface of the groove and the groove The maximum vertical distance of the top surface is not greater than the diameter of the fiber unit, which ensures a compact structure when the fiber unit is laid out, reduces the gap in the groove, further reduces the resistance of the air in the gap to the sound wave, and improves the sensitivity of the sound wave signal detection; and along the The inner surface of the groove is filled with a polyester fiber composite tape of a single-sided composite polyester film, the composite polyester film face of the polyester fiber composite tape is airtight, and the non-composite polyester film of the polyester fiber composite tape The surface has porous characteristics, the polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, the non-composite polyester film surface of the polyester fiber composite tape faces the optical fiber unit, and the polyester fiber composite tape is used to The porous surface of the fiber composite belt improves the sound wave absorption effect, forms a sound-accommodating cavity in the entire groove, and improves the sensitivity of optical fiber detection.

On the other hand, some embodiments of the present application provide a high-strength lateral pressure-resistant sensing optical cable, which sequentially includes a central strength member, an optical fiber unit layer, a first wrapping tape, and a first outer sheath from the inside to the outside , the outer armor layer, the second wrapping tape, and the second outer sheath structure design, the outer armor layer, the inner and outer two wrapping tapes, and the inner and outer two outer sheaths are set, which further enhances the sensing optical cable. The overall strength, as well as the enhanced bending resistance, lateral pressure resistance and tensile performance of the sensing optical cable, meet the laying requirements under various harsh conditions.

In order to make the above-mentioned purpose, features and advantages of the present application more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, so It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 shows a schematic structural view of a sensing optical cable with enhanced sensitivity of the present application;

Fig. 2 shows a schematic structural diagram of a groove array of a sensing optical cable with enhanced sensitivity in the present application;

Fig. 3 shows a schematic structural view of a groove of a sensor optical cable with enhanced sensitivity in the present application;

Fig. 4 shows a second schematic diagram of the groove array structure of a sensing optical cable with enhanced sensitivity in the present application;

Fig. 5 shows a schematic diagram of an enhanced structure of a sensing optical cable with enhanced sensitivity in the present application.

Among them: 1-central strength member, 2-optical fiber unit layer, 3-first wrapping tape, 4-first outer sheath, 5-rip rope, 6-strengthening element, 7-optical fiber unit, 8-groove , 9-groove array, 10-outer armor layer, 11-second wrapping tape, 12-second outer sheath, 13-top surface of groove, 14-side wall of groove, 15-groove the underside.

Detailed ways

The term "comprising" in the description and claims of the present application and the drawings is synonymous with "including", "containing" or "characterized by", and is inclusive or open-ended, and does not exclude Additional unrecited elements or method steps. "Comprising" is a technical term used in claim language to mean that the stated elements are present, but other elements may be added and still form a construction or method within the scope of the claim.

It should be noted that like numerals and letters denote similar items in the following drawings, therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings, In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance. In this application the term "about" is meant to include minor variations (up to +/- 10%) from the stated value.

The existing sensing optical cable is used as the carrier of the optical fiber distributed sensing system. In the actual application process, most of the optical fibers in the cable are placed directly. The detection sensitivity is not high. At the same time, affected by the application scenario, the sensing optical cable needs to have certain mechanical strength, such as tensile and lateral pressure resistance, to avoid damage to the optical cable during laying.

Based on this, an embodiment of the present invention provides a sensing optical cable with enhanced sensitivity. The sensing optical cable includes a central strength member and an optical fiber unit layer other than the central strength member. The central strength member is an elastic body or A thermoplastic elastic material nested with metal or non-metal elements, the optical fiber unit layer includes optical fiber units that are continuously helically wound around the central strength member; the surface of the central strength member is spirally distributed with a continuous groove array along the length direction, so The optical fiber unit is filled in the grooves of the groove array, and the maximum vertical distance between the optical fiber unit and the inner surface of the groove and the top surface of the groove is not greater than the diameter of the optical fiber unit; along the groove The inner surface of the groove is filled with a polyester fiber composite tape of a single-sided composite polyester film, the composite polyester film face of the polyester fiber composite tape is airtight, and the non-composite polyester film surface of the polyester fiber composite tape has a porous Characteristic, the polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, and the non-composite polyester film surface of the polyester fiber composite tape faces the optical fiber unit. A sensing optical cable with enhanced sensitivity in the above embodiment, the optical fiber unit in the cable is helically wound and arranged to ensure the stable transmission performance of the optical cable, and at the same time increase the length of the optical fiber within the unit length of the optical cable, further broaden the detectable range, and improve Detection sensitivity; at the same time, the central reinforcement is made of a sensitive material, which can reduce the loss of external transmission energy and improve the detection sensitivity of the sensing optical cable; furthermore, in this application, a continuous array of grooves is distributed on the surface of the central reinforcement to accommodate Multiple optical fiber units, increase the test signal channel, in case of fiber breakage, provide a backup line, and at the same time, the optical fiber unit is filled in the groove, so compared with the direct helical winding of the optical fiber unit on the surface of the central strength member , reducing the gap between the central reinforcement and the sheath, reducing the resistance of the air in the gap to the sound wave, improving the sensitivity of the sound wave signal detection, and the distance between the optical fiber unit and the inner surface of the groove and the groove The maximum vertical distance of the top surface is not greater than the diameter of the fiber unit, which ensures a compact structure when the fiber unit is laid out, reduces the gap in the groove, further reduces the resistance of the air in the gap to the sound wave, and improves the sensitivity of the sound wave signal detection; and along the The inner surface of the groove is filled with a polyester fiber composite tape of a single-sided composite polyester film, the composite polyester film face of the polyester fiber composite tape is airtight, and the non-composite polyester film of the polyester fiber composite tape The surface has porous characteristics, the polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, the non-composite polyester film surface of the polyester fiber composite tape faces the optical fiber unit, and the polyester fiber composite tape is used to The porous surface of the fiber composite belt improves the sound wave absorption effect, forms a sound-accommodating cavity in the entire groove, and improves the sensitivity of optical fiber detection.

In addition, some embodiments of the present application also provide a high-strength and lateral pressure-resistant sensing optical cable with enhanced sensitivity, which sequentially includes a central strength member, an optical fiber unit layer, a first wrapping tape, a first outer The structural design of the sheath, the outer armor layer, the second wrapping tape, and the second outer sheath is equipped with an outer armor layer, two inner and outer wrapping tapes, and an inner and outer two outer sheaths, which further enhances the sensing The overall strength of the optical cable, as well as the enhanced bending resistance, lateral pressure resistance, and tensile performance of the sensing optical cable, meet the laying requirements under various harsh conditions.

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

Example 1

A kind of sensing optical cable with enhanced sensitivity is provided in the present embodiment 1, as shown in Fig. 1, the first layer including central strength member 1, optical fiber unit layer 2, polyimide film (PI film) successively from inside to outside A wrapping tape 3, a first outer sheath 4. The optical fiber unit layer 2 adopts at least one optical fiber unit 7 to be continuously helically wound along the central strength member 1 . As shown in FIGS. 1-2 , a continuous array of grooves 9 is helically distributed on the surface of the central strength member 1 along the length direction, and the optical fiber unit 7 is filled in the grooves 8 of the array of grooves 9 .

The central reinforcement 1 is an elastomer, such as thermoplastic polyolefin elastomer (TPO), thermoplastic polyester elastomer (TPEE), thermoplastic vulcanizate (TPV), for example, can be selected from polyethylene elastomer, polyolefin elastomer, polypropylene One or a combination of elastomers, for example, may be thermoplastic polyurethane elastomer (TPU).

In some other embodiments, the central strength member 1 is a thermoplastic elastic material embedded with metal or non-metal elements, which can strengthen the strength of the optical cable without loss of measurement sensitivity. Thermoplastic elastic material, such as thermoplastic polyolefin elastomer (TPO), thermoplastic polyester elastomer (TPEE), thermoplastic polyurethane elastomer rubber (TPU), or thermoplastic vulcanizate (TPV), etc. The metal element can be, for example, a steel wire. The non-metallic elements may be fiber reinforced plastics (FRP), such as glass fiber reinforced plastic rods, aramid fiber reinforced plastic rods, carbon fiber reinforced plastic rods and the like.

PI film is a thin film insulating material, which is formed by polycondensation of pyromellitic dianhydride (PMDA) and diaminodiphenyl ether (ODA) in a strong polar solvent, and then cast into a film and then imidized. Yellow and transparent, relative density 1.39-1.45. Polyimide film has excellent high and low temperature resistance, electrical insulation, adhesion, radiation resistance, and medium resistance. It can be used for a long time in the temperature range of -269 ° C to 280 ° C, and can reach 400 ° C in a short time high temperature.

The first outer sheath 4 can adopt thermoplastic elastic material, such as TPU, TPV, TPO, TPEE etc., this kind of material can be used as sound-absorbing material, has good sound-absorbing effect, can improve the sensitivity of optical cable to sound wave signal detection; Simultaneously Thermoplastic elastomer materials can improve the softness and elasticity of the molding unit, and ensure better oil resistance, water resistance, cold resistance, and mold resistance.

In some other embodiments, for example, for some scenarios with high usage requirements, such as oil mines, the first outer sheath 4 can be made of fluorine plastic to improve the temperature resistance level of the optical cable.

Reinforcement elements 6 are arranged in the first outer sheath 4, and the reinforcement elements 6 can be fiber reinforced plastics (FRP) or metal elements, such as phosphating steel wires, galvanized steel wires, galvanized steel strands or copper-plated steel Stranded wires, etc., the setting of the reinforcing element 6 further enhances the bending resistance of the optical cable.

A tearing rope 5 is buried between the first outer sheath 4 and the PI film, the tearing rope 5 is parallel to the axis of the optical cable, and at least one tearing rope 5 is provided. In some other embodiments, there are at least two tearing cords 5, and the at least two tearing cords 5 are evenly distributed along the circumference of the optical cable. The setting of the tearing rope facilitates the stripping of the optical cable, and facilitates the later maintenance and repair of the optical cable after laying.

The optical fiber unit 7 is a tight-cuffed optical fiber, that is, a tight-sleeved optical fiber, with an outer diameter of 0.6 mm to 3.0 mm. In some other implementation examples, the optical fiber unit can also be a loose-buffered optical fiber with an outer diameter of 0.6 mm to 3.0 mm, and the number of optical fiber cores in each loose-buffered structure can be no less than 1 core. For example, in some embodiments, the optical fiber unit is a single-core optical fiber, the winding pitch is 0.1 mm˜100 mm, and the winding angle range is 10°<α<90°. For example, in some embodiments, the optical fiber unit is a multi-core optical fiber, the winding pitch is 15mm-300mm, and the winding angle range is 10°<α<90°.

In this embodiment, the optical fiber unit adopts single-mode optical fiber, which has excellent bending resistance. When the core diameter of φ7.5mm is wound once, the macrobending loss of the optical fiber is 1550nm≤0.01dB; stable optical fiber transmission performance is guaranteed after cabled , 1550nm attenuation does not exceed 1.0dB/km.

In the sensing optical cable in this embodiment, the optical fiber unit in the cable is helically wound and arranged to ensure the stable transmission performance of the optical cable, while increasing the length of the optical fiber within the unit optical cable length, further broadening the detectable range, and improving the detection sensitivity; at the same time, the center is strengthened The parts are made of sensitizing material, which can reduce the loss of external transmission energy and improve the detection sensitivity of the sensing optical cable. The outer sheath and the reinforcing elements therein protect the optical cable, enhancing the overall strength and bending resistance of the sensing optical cable. With its excellent high and low temperature resistance, electrical insulation, adhesion, radiation resistance, and medium resistance, PI film also plays a certain role in protecting the optical fiber unit.

In order to further enhance the sensitivity of the sensing optical cable, as shown in Figure 1-2 in this embodiment, a continuous groove array 9 is spirally distributed on the surface of the central reinforcement 1, and the transverse section of the groove 8 of the groove array 9 is arc-shaped Or square, the maximum depth H and maximum width W of the groove should not be less than the diameter d of the fiber unit. By setting the groove 8, the optical fiber unit 7 is filled in the groove 8, compared with the direct spiral winding of the optical fiber unit on the surface of the central strength member 1, the gap between the central strength member and the sheath is reduced, and the gap in the gap is reduced. The resistance of air to sound waves improves the sensitivity of sound wave signal detection.

Generally, in order to ensure a compact structure when the fiber unit is laid out, when a single fiber unit is accommodated, the size range of the groove satisfies d≤H≤d+d ₀ , d≤W≤d+d ₀ ;

When accommodating n (n≥2) optical fiber units, the size range of the groove satisfies:

Among them: d _f is the equivalent diameter of n fiber units; d ₀ is the free coefficient, that is, the maximum vertical distance between the fiber unit and the inner surface of the groove after filling the groove, 0≤d ₀ ≤d, d is the diameter of the fiber unit . When the free coefficient _d0 is set so that the optical fiber unit 7 is filled in the groove 8 of the groove array 9, the distance between the optical fiber unit and the inner surface of the groove (as shown in Figure 3, including the side of the groove) is satisfied. The maximum vertical distance between the wall 14 and the bottom surface 15) of the groove and the top surface 13 of the groove is not greater than the diameter of the fiber unit, which ensures that the fiber unit has a compact structure when it is laid out, reduces the gap in the groove, and further reduces the gap The resistance of the air in the air to the sound wave improves the sensitivity of the sound wave signal detection.

A plurality of continuous groove arrays 9 are distributed on the surface of the central strength member 1 of this embodiment to accommodate a plurality of optical fiber units, increase test signal channels, and provide backup lines in case of fiber breakage in the optical fiber, as shown in Figures 2 and 4 shown. Each groove array 9 includes at least two grooves 8 .

In some embodiments, n grooves 8 form a groove array 9, and the grooves 8 may be closely connected to each other, or have a first distance d ₁ , where 0≦d1.

In some embodiments, the second distance d2 between the groove arrays 9 can be adaptively changed with the closely wound pitch of the optical fiber unit. Generally, 0≤d1<d2.

In this embodiment, in order to further improve the sensitivity, in the above structure, when the groove is filled with multiple optical fiber units, the size of the groove and the internal gap will increase accordingly, and a single-sided composite polymer fiber can be filled first along the surface of the groove. Polyester fiber composite tape of ester film, the composite polyester film surface of the polyester fiber composite tape is airtight, the non-composite polyester film surface of the polyester fiber composite tape has porous characteristics, and the polyester fiber composite tape The polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, and the non-composite polyester film surface of the polyester fiber composite tape faces the optical fiber unit. The surface of the polyester film is close to the inner surface of the groove, and the surface of the non-composite polyester film is porous and faces the optical fiber unit. On the one hand, it can play a buffer role, and on the other hand, it can take advantage of the porous surface of the composite polyester tape. , improve the sound wave absorption effect, form a sound-accommodating cavity in the entire groove, and improve the sensitivity of optical fiber detection.

In this embodiment 1, a sensing optical cable with enhanced sensitivity is provided. The optical fiber unit in the cable is helically wound and laid out to ensure the stable transmission performance of the optical cable while increasing the length of the optical fiber per unit cable length and further expanding the detectable range. , to improve the detection sensitivity; at the same time, the central reinforcement is made of a sensitizing material, which can reduce the loss of external transmission energy and improve the detection sensitivity of the sensing optical cable; furthermore, in this embodiment 1, continuous grooves are distributed on the surface of the central reinforcement array, to accommodate multiple fiber units, increase the test signal channel, and provide a backup line in case of fiber breakage; The surface of the reinforcement reduces the gap between the central reinforcement and the sheath, reduces the resistance of the air in the gap to the sound wave, and improves the sensitivity of the detection of the sound wave signal. At the same time, it is filled with a single-sided composite polyester film along the inner surface of the groove The polyester fiber composite tape, the polyester film surface of the polyester fiber composite tape is close to the inner surface of the groove, and the non-composite polyester film surface has porous characteristics, and the surface porous characteristics of the composite polyester tape are used to improve the sound wave Absorption effect, forming a sound-accommodating cavity in the entire groove, improving the sensitivity of optical fiber detection.

In this embodiment, the continuous helical winding of the optical fiber unit around the central strength member in the sensing optical cable can be equidistant helical winding, and the uniform winding method can realize fully distributed signal collection along the sensing optical cable, and there is no sensing blind zone. In some other embodiments, the continuous helical winding of the optical fiber unit around the central strength member in the sensing optical cable can also be a locally dense winding manner, which can obtain a highly sensitive and small-sized sensing unit, and obtain a highly sensitive sensing unit array. In some other embodiments, the sensing optical cable may include a plurality of repeating segments of equal length, and the winding pitch of the optical fiber units in the repeating segments is set to vary. For example, it can be a random distribution change, an arithmetic sequence change or a geometric sequence change. In this embodiment, the sensitivity of the sensing optical cable can be presented as a combined distribution of strength and weakness, which can adapt to the detection of signals (such as sound waves, vibration signals) The strength of the area changes, the weaker signal is received by the high-sensitivity sensor cable, and the stronger signal can be received by the low-sensitivity sensor cable, maintaining the spatial resolution of the sensor cable, so that the sensor cable can be long The distance is laid, and compared with the sensing optical cable design of the whole section of densely wound optical fiber, the application reduces the application length of the optical fiber and saves the cost.

In some other embodiments, the optical fiber unit is in the shape of a flat ribbon. At this time, the maximum depth H and the maximum width W of the groove should not be smaller than the thickness and width of the flat ribbon-shaped optical fiber unit. There is at least one bare optical fiber in the optical fiber unit, which is uniformly spaced in the flat ribbon of the optical fiber unit and continuously distributed along the length direction of the optical fiber unit. In some embodiments, the bare optical fiber is continuously sinusoidally distributed within the flat ribbon of the optical fiber unit. When the optical fiber unit is in the shape of a flat ribbon, the diameter of the optical fiber unit is equivalent to the diameter of its circumscribed circle. In this embodiment, the flat ribbon structure can better fit on the surface of the central strengthening element, reduce the gap, and improve the sensitivity of the detection signal. At the same time, the continuous sinusoidal distribution of the bare optical fiber in the resin further improves the optical fiber per unit cable length. length, to further broaden the detectable range and improve detection sensitivity.

Example 2

The difference between Embodiment 2 and Embodiment 1 lies in the design of the overall structure of the optical cable, especially the design of the reinforcement and the protection layer.

As shown in Figure 5, it includes a central strength member 1, an optical fiber unit layer 2, a first wrapping tape 3, a first outer sheath 4, an outer armor layer 10, a second wrapping tape 11, The second outer sheath 12. The optical fiber unit layer 2 adopts nine optical fiber units 7 to be continuously helically wound along the central strength member 1 . As shown in FIG. 5, three continuous groove arrays 9 are helically distributed on the surface of the central strength member 1 along the length direction, and each groove array 9 has three grooves 8, and the optical fiber unit 7 is filled in Inside the grooves 8 of the groove array 9 .

The central reinforcement 1 is an elastomer, such as thermoplastic polyolefin elastomer (TPO), thermoplastic polyester elastomer (TPEE), thermoplastic vulcanizate (TPV), for example, can be selected from polyethylene elastomer, polyolefin elastomer, polypropylene One or a combination of elastomers, for example, may be thermoplastic polyurethane elastomer (TPU). In some other embodiments, the central reinforcement 1 is a thermoplastic elastic material embedded with metal or non-metal elements. Thermoplastic elastic material, such as thermoplastic polyolefin elastomer (TPO), thermoplastic polyester elastomer (TPEE), thermoplastic polyurethane elastomer rubber (TPU), or thermoplastic vulcanizate (TPV), etc. The metal element can be, for example, a steel wire. The non-metallic elements may be fiber reinforced plastics (FRP), such as glass fiber reinforced plastic rods, aramid fiber reinforced plastic rods, carbon fiber reinforced plastic rods and the like.

The first outer sheath 4 and the second outer sheath 12 can be made of thermoplastic elastic materials, such as TPU, TPV, TPO, TPEE, etc., such materials can be used as sound-absorbing materials, have good sound-absorbing effect, and can improve the optical fiber cable The sensitivity of acoustic signal detection; at the same time, the thermoplastic elastomer material can improve the softness and elasticity of the molding unit, and ensure better oil resistance, water resistance, cold resistance, and mold resistance. In some other embodiments, for example, for some scenarios with high usage requirements, such as oil mines, the first outer sheath 4 or the second outer sheath 12 can be made of fluoroplastics to improve the temperature resistance level of the optical cable.

There is an outer armor layer 10 outside the first outer sheath 4 . The outer armor layer 10 can be steel wire or fiber reinforced plastic (FRP), such as glass fiber reinforced plastic rods, aramid fiber reinforced plastic rods, carbon fiber reinforced plastic rods and the like. The double-layer armor increases the tensile and lateral pressure resistance of the sensing optical cable, making the sensing optical cable more suitable for underground laying.

The first wrapping tape 3 and the second wrapping tape 11 can be polyimide film (PI film), non-woven fabric, water-blocking cloth, polyester tape (mylar tape), polypropylene wrapping tape, non-woven Cloth wrapping tape, PVC wrapping tape, polytetrafluoroethylene tape (PTFE), glass fiber cloth, mica tape, etc. The first wrapping tape 3 and the second wrapping tape 11 play the role of cushioning and padding, and the first wrapping tape 3 can also protect the inner optical fiber unit layer 2, and simultaneously, according to the selection of different materials, respectively play waterproof, heat insulation, Different functions such as anti-corrosion or anti-aging.

Refer to the description in Embodiment 1 for the rest of the content, which will not be repeated here.

In this embodiment, a lateral pressure-resistant multi-core sensing optical cable includes, from inside to outside, a central strength member 1, an optical fiber unit layer 2, a first wrapping tape 3, a first outer sheath 4, and an outer armor layer. 10. The structural design of the second wrapping tape 11 and the second outer sheath 12 is provided with an outer armor layer, two inner and outer wrapping tapes, and an inner and outer two outer sheaths, which further enhances the overall strength of the sensing optical cable. Strength, and enhanced bending resistance, lateral pressure resistance, and tensile properties of the sensing optical cable.

The embodiments of the present application have been introduced in detail above, and specific examples have been used in this paper to illustrate the principles and implementation methods of the present application. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application; meanwhile, for Those skilled in the art will have changes in specific implementation methods and application scopes based on the ideas of the present application. In summary, the contents of this specification should not be construed as limiting the present application.

Claims (8)

1. An enhanced sensitivity sensing optical cable, comprising a central strength member and a fiber unit layer outside the central strength member, wherein the central strength member is an elastomer or a thermoplastic elastomer material in which metal or nonmetal elements are nested, and the fiber unit layer comprises fiber units spirally wound around the central strength member;

the surface of the central reinforcing member is spirally distributed with a continuous groove array along the length direction, the optical fiber units are filled in the grooves of the groove array, the maximum depth and the maximum width of the grooves are not less than the diameter of the optical fiber units, and when a single optical fiber unit is accommodated, the size range of the maximum depth H and the maximum width W of the grooves is satisfied: d is not less than H and not more than d + d ₀ ，d≤W≤d+d ₀ Wherein d is the fiber unit diameter; when n optical fiber units are accommodated, the size range of the groove satisfies the following conditions: d _f <H≤d _f +d ₀ Wherein: n is not less than 2,d _f Is the equivalent diameter of n optical fiber units; d ₀ D is a free coefficient, i.e. the maximum vertical distance of the optical fiber unit from the inner surface of the groove after the groove is filled, 0 ≦ d ₀ ≤d；

The polyester fiber composite belt with the single-sided composite polyester film is filled along the inner surface of the groove, the composite polyester film surface of the polyester fiber composite belt is airtight, the non-composite polyester film surface of the polyester fiber composite belt has a porous characteristic, the polyester film surface of the polyester fiber composite belt is tightly attached to the inner surface of the groove, and the non-composite polyester film surface of the polyester fiber composite belt faces the optical fiber unit.

2. An enhanced sensitivity sensing optical cable according to claim 1, wherein the transverse cross-section of said groove is arc-shaped and square-shaped.

3. An enhanced sensitivity sensing optical cable according to claim 1, wherein said sensing optical cable comprises a plurality of repeating segments of equal length, the winding pitch of the optical fiber units in said repeating segments being arranged variably.

4. An enhanced sensitivity sensing cable as claimed in claim 1, wherein there are more than two of said groove arrays, and the grooves of said groove arrays have a first pitch d between them ₁ (ii) a A second spacing d2 is formed between the groove arrays, and d1 is more than or equal to 0 and less than d2.

5. An enhanced sensitivity sensing cable as claimed in claim 1, wherein said optical fiber unit is in the form of a flat ribbon.

6. An enhanced sensitivity sensing optical cable according to claim 5, wherein the number of the bare fibers in the optical fiber unit is at least one, and the bare fibers are uniformly spaced and axially continuously distributed in the flat ribbon of the optical fiber unit, or the bare fibers are continuously sinusoidally distributed in the flat ribbon of the optical fiber unit.

7. The sensing cable of any one of claims 1 to 6, wherein the optical fiber unit layer is further covered with a first wrapping tape and a first outer sheath from inside to outside, and the first outer sheath is provided with a reinforcing element, wherein the reinforcing element is a metal element or Fiber Reinforced Plastic (FRP).

8. The sensing cable with enhanced sensitivity according to any one of claims 1 to 6, wherein the optical fiber unit layer is further covered with a first wrapping tape, a first outer sheath, an outer armor layer, a second wrapping tape, and a second outer sheath from inside to outside.

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